The present invention relates to an electrically powered pump which is used as an oil pump, etc., and particularly relates to an improvement of an electrically powered pump in which a motor section disposed on the radial outside of the electrically powered pump and a pump section disposed on the radial inside of the electrically powered pump are substantially integrally formed with each other.
Japanese Patent Application Unexamined Publication No. 2003-129966 discloses an electrically powered oil pump for use in an internal combustion engine and an automatic transmission for vehicles. The electrically powered oil pump of this conventional art has the construction of a generally known trochoid pump in which an outer rotor having permanent magnets is directly rotatably driven by coils disposed on the side of a housing, instead of the construction of a prior art in which an electric motor and a pump are connected with each other in series. Specifically, in the electrically powered oil pump of this conventional art, annular permanent magnets are fixed onto an outer circumferential surface of the outer rotor, and a core and coils are disposed on a housing which surrounds the outer rotor and the permanent magnets. The former corresponds to a rotor of a motor, and the latter corresponds to a stator of the motor. Further, an inner rotor of the generally known trochoid pump is disposed on the inner radial side of the outer rotor, and is rotated to follow rotation of the outer rotor. Thus, the electrically powered oil pump of this conventional art performs a pumping action thereof.